NEW YORK (CBSNewYork) – The doctor who will perform surgery on Alex Rodriguez’s ailing left hip isn’t shocked that the Yankees’ slugger slumped mightily throughout the playoffs.

In fact, he’s surprised A-Rod was “able to play at all with a hip that looked like that.”

“Most people would not be able to play with a hip function like this and the imaging that looked like his,” Dr. Bryan Kelly told the New York Post.

The Yankees announced last month that Rodriguez would need surgery on his hip to repair a torn labrum and bone impingement. He was expected to undergo the procedure in mid-January.

The Post reported that “the surgery will still not be performed for two to four more weeks.” The team said A-Rod would likely be out four-to-six months. The 37-year-old had surgery on his right hip in March of 2009 and returned two months later. This operation will be “similar but not identical,” the Yankees said.

A-Rod hit .272 with 18 home runs and 57 RBIs in 2012. He drew the ire of Yankees fans during a postseason that included poor play, benchings and a flirting controversy at Yankee Stadium.

Kelly said A-Rod’s ability to hit high-speed pitches, with “zero degrees of motion through his hip,” became a “mechanical impossibility.”

“He was not able to play at the level he needed to, directly as a result of the injury he has,” he told the Post. “I looked at the pictures, and there is no doubt the injury was what caused the reduction of performance.”

Kelly attributed the injury to a combination of hereditary and developmental factors — not A-Rod’s admitted steroid use.

“I can say with 100 percent certainty this is not a steroid injury at all,” said Kelly. “This is a mechanical injury, and mechanics are something you are born with.”

The Yankees owe $114 million to A-Rod over the final five years of his deal.

OK, but will he ever be a shell of the player he once was? Sound off with your thoughts and comments in the section below…